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1.
壳聚糖对水分胁迫下青稞幼苗部分生理指标的影响 总被引：1，自引：0，他引：1
以青稞为实验材料,通过水培实验法探究了不同浓度壳聚糖（CTS）预处理对12％聚乙二醇（PEG）胁迫下青稞幼苗部分生理指标的影响．结果显示,12％PEG胁迫下青稞幼苗叶片含水量、叶绿素相对含量和可溶性蛋白含量均下降,经适宜浓度的CTS预处理,能在一定程度上抑制青稞幼苗含水量的下降,提高叶绿素相对含量和可溶性蛋白含量．因此,适宜浓度的壳聚糖可以增强青稞幼苗的抗旱能力,减轻水分胁迫对青稞幼苗造成的伤害． 相似文献
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通过盆栽试验对土壤干旱条件下济麦21幼苗期、拔节期、扬花期和灌浆期脯氨酸含量、可溶性糖含量、膜透性、POD活性和总叶绿素含量的动态变化进行了初步研究.结果表明,不同水分处理下,脯氨酸、可溶性糖含量和总叶绿素含量在不同生长发育时期的动态变化趋势基本一致,幼苗期到拔节期急剧增大,拔节期之后均呈下降趋势;质膜透性从幼苗期到灌浆期均呈上升趋势;POD活性从幼苗期到灌浆期均呈下降趋势.随干旱胁迫的加剧,脯氨酸、可溶性糖含量、质膜透性和POD活性均显著高于正常水分.不同水分处理的总叶绿素含量在幼苗期没有差异,干旱胁迫处理的总叶绿素含量在拔节期、扬花期和灌浆期均显著降低. 相似文献
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以青稞幼苗为试材,采用营养液水培法研究了200mmol／L NaCl胁迫对青稞幼苗叶片相对含水量（RWC）、叶绿素、丙二醛（MDA）、脯氨酸含量的影响．结果显示,在200mmol／L NaCl胁迫2,4,6,8d后,青稞幼苗叶片相对含水量、叶绿素含量随胁迫的进行而不断下降,其中叶绿素含量在前4d下降尤其明显;MDA和脯氨酸含量则显著上升．表明200mmol／L NaCl胁迫对青稞幼苗造成了严重的生理伤害． 相似文献
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水分胁迫下亚精胺对小麦幼苗蛋白质含量与蛋白酶活性的影响 总被引：1，自引：0，他引：1
研究了水分胁迫下亚精胺对小麦幼苗相对含水量、叶绿素总量、蛋白质含量和蛋白酶活性的影响。结果显示,亚精胺预处理延缓水分胁迫下小麦幼苗叶片含水量、叶绿素含量和蛋白质含量的下降,抑制蛋白酶活性的上升。表明亚精胺预处理对水分胁迫的小麦幼苗具有防衰抗旱的保护作用。 相似文献
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目的:探究镧对大豆铝胁迫的缓解效应;方法:以铝敏感大豆BD2为材料,进行50μmol/L铝胁迫处理,然后添加不同浓度氯化镧(10、100和1000 mg L/L)测定大豆幼苗抗氧化及光合指标;结果:与对照组相比较,铝胁迫导致大豆幼苗根系伸长率、根冠比、鲜重及干重显著降低,叶片SOD、POD活性显著降低,且MDA含量显著升高,叶绿素与类胡萝卜素含量、光合速率、蒸腾速率、气孔导度及胞间CO_2浓度也均显著下降;而与铝胁迫处理相比,不同浓度镧处理对大豆幼苗根长、鲜重与干重、SOD与POD活性有不同程度地促进作用,并显著降低MDA含量,同时提高叶绿素与类胡萝卜素含量,增强光合速率、蒸腾速率、气孔导度和胞间CO_2浓度,其中以10 mg/L镧处理效果最好;结论:适宜浓度的镧处理能够通过增强大豆幼苗的抗氧化能力,提高其光合性能,提高大豆幼苗对铝胁迫的适应能力,有效缓解铝对大豆幼苗生长的毒害。 相似文献
7.
叶面喷施黄腐酸钠可显著提高猕猴桃幼苗的抗旱保水能力,表现为降低叶面蒸腾强度,增加气孔扩散阻力,提高幼苗的生物量和叶片的叶绿素含量,在干旱胁迫条件下尤为明显。叶面喷施黄腐酸钠还可使处于干旱胁迫的猕猴桃幼苗叶片内脯氨酸含量比对照提高近一倍,即使在水分充足时,也能使叶片内脯氨酸含量比对照增加73.6％。 相似文献
8.
Pb2+、Cd2+对青稞幼苗生理指标的影响 总被引：2，自引：0，他引：2
采用室内水培法,研究了50mg/L浓度的Pb2 ,Cd2胁迫对青稞幼苗的叶片相对含水量、叶绿体色素和可溶性蛋白质含量的影响.结果显示,随着胁迫时间的延长,50mg/L Pb2 胁迫的青稞幼苗叶片相对含水量变化不大,叶绿素a和类胡萝卜素含量先上升后下降,叶绿素b和可溶性蛋白质含量有所降低;50mg/LCd2 胁迫的青稞幼苗叶片相对含水量、叶绿素a、叶绿素b和可溶性蛋白质含量均显著下降,类胡萝卜素含量先明显升高后降低.表明50mg/L Pb2 对青稞幼苗胁迫程度不大,而50mg/L Cd2 胁迫对青稞幼苗造成了严重伤害.因此,同一浓度的重金属离子Pb2 ,Cd2 对青稞幼苗的胁迫程度不同. 相似文献
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《怀化学院学报》2016,(5)
为探讨虎耳草人工栽培的水分条件,利用LI-6400便携式光合仪研究了不同干旱条件下盆栽虎耳草的光合作用,同时采用LC-20AT高效液相色谱对虎耳草中没食子酸和岩白菜素含量进行了测定.结果表明:土壤体积含水量随处理天数的增加显著减少,处理42 d后,体积含水量仅5.8%.净光合速率随干旱加剧显著降低;蒸腾速率在干旱14 d时有所上升,达4.08 mmol·m~(-2)·s~(-1),此时气孔导度也有所升高.叶绿素荧光参数值显示,光系统Ⅱ反应中心开放程度、光化学效率、电子传递速率等都随干旱加剧而降低,处理28 d时下降最显著.干旱能显著降低虎耳草的生物产量,处理42天时,虎耳草干重仅10.7 g·pot~(-1),但适度的干旱能提高有效成分含量,没食子酸和岩白菜素含量在干旱14 d时最高,分别为2.11 mg·g~(-1)及4.13 mg·g~(-1).结论:虎耳草较耐旱,干旱处理14 d时仍能维持一定的光合作用,保证生物产量的积累,并显著提高有效成分含量,人工种植虎耳草时可适度地控制水分给予. 相似文献
10.
酸胁迫对玉米幼苗生理生化指标的影响 总被引：1，自引：0，他引：1
采用沙培法研究了酸胁迫对玉米幼苗生理生化指标的影响.研究结果表明:在酸胁迫下,玉米幼苗叶片SOD活性下降,MDA含量上升,叶绿素含量下降;根长变短,根相对含水量下降,根系活力下降,并随着酸胁迫程度的加深,这些指标的变化越明显. 相似文献
11.
罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
12.
邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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Rachel Zupek 《海外英语》2007,(11):40-41
我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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YANGShiguo 《重庆大学学报(英文版)》2004,3(1):86-88
The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex. 相似文献